Pollution alert today, heat index could reach 100 degrees

Nancy Stone/Chicago Tribune

Jose Hernandez, of Chicago, fishes off the breakwall at Montrose Avenue. He goes out fishing about once a week and usually catches small salmon. At 7 a.m., the sun was already heating up the Chicago lakefront.

Jose Hernandez, of Chicago, fishes off the breakwall at Montrose Avenue. He goes out fishing about once a week and usually catches small salmon. At 7 a.m., the sun was already heating up the Chicago lakefront. (Nancy Stone/Chicago Tribune)

Staff report

As Chicago-area residents suffer through an air pollution action day and high humidity making it feel like it's 100 degrees, the National Weather Service confirmed this July was one of the hottest on record.

The Illinois Environmental Protection Agency issued the air pollution alert for Cook County and the seven collar counties through this evening. The alert also covers several counties in Wisconsin and Indiana.

People with pulmonary and respiratory diseases like asthma are especially sensitive during this time and are asked to limit their outdoor activities, officials said.

Today's forecast calls for temperatures in the lower to mid 90s, with humidity levels pushing the heat index to 100 degrees in some areas.

Tuesday is expected to be even muggier, with temperatures in the mid-90s and the heat index as high as 105, according to the National Weather Service. By Wednesday, the highs will dip into the mid-80s.

Meanwhile, the National Weather Service issued a statement confirming that this July was one of only three Julys since 1872 in Chicago that have seen highs of 80 degrees or greater on all but one day of the month.

The only year that all 31 days in July saw a high of 80 or greater was in 1955, the warmest July on record in Chicago, which was part of the city's warmest summer.

The city also saw highs of 80 or greater on 30 of 31 days in 2010 and 1999, the only two other times that has happened, according to the weather service.